1. Field of the Invention
The present invention relates to membranes of polymers. In particular, the present invention relates to organic/inorganic hybrid polymer blend membranes.
2. Discussion of the Related Art (State of the Art and its Disadvantages)
The state of the art regarding acid chloride/inorganic hybrid composites is disclosed in the following article: “Chemical modification of a Nafion™ sulfonyl fluoride precursor via in situ sol-gel reactions,” by A. J. Greso, R. B. Moore, K. M. Cable, W. L. Jarrett, K. A. Mauritz Polymer 38, 1345-1356 (1997)
Nafion™ sulfonyl fluoride precursor membranes are preswollen in perfluorohydrophenanthrene and immersed in 3-aminopropyltriethoxysilane. Thereafter excess silane is washed out with EtOH. Hybrids are formed, in which by hydrolysis of silane and by reaction of silanes with SO2F groups SiO2 networks partially cross-linked with the polymer are formed in the membrane matrix.
Disadvantage of the described system is that the sol/gel reaction takes place in a preformed membrane and consequently the content of the inorganic polymer phase formed by hydrolysis, of the polymer composite can not be set at will.
Also hybrid systems of nonionic polymers and metallic respectively elemental oxides have been described in the literature:
(a) composites of poly(n-butylmethacrylate) and titanium oxide, made by water vapor hydrolysis of titan alkoxides, which had been added to alcoholic solutions of a poly(n-butylmethacrylate) polymer solution, in the polymer matrix after evaporation of the solvent. This procedure is disclosed in “Novel Poly(n-Butyl Methacrylate)/Titanium Oxide Alloys Produced by the Sol-Gel process for Titanium Alkoxides,” by K. A. Mauritz, C. K. Jones, J. Appl. Polym. Sci. 40, 1401-1420 (1990).
(b) composite membranes of polyetherimide and nanodispersed silicium oxide, made by hydrolysis of TEOS in solutions of polyetherimide Ultem® in NMP by addition of 0.15 M HCl solution. After hydrolysis dense or phase inversed membranes are made from this polymer solution. Compatibility of the inorganic with the organic phase was obtained by extra addition of 3-aminopropyltrimethoxysilane (AS). This procedure is disclosed in “Novel Poly(n-Butyl Methacrylate)/Titanium Oxide Alloys Produced by the Sol-Gel process for Titanium Alkoxides,” by K. A. Mauritz, C. K. Jones, J. Appl. Polym. Sci. 40, 1401-1420 (1990